On 30 June 2015, Real Madrid exercised their buyback clause and Vázquez returned to the club. He made his debut on 12 September in a 6–0 away win over his former team Espanyol, and his first start came a week later, in a 1–0 home defeat of Granada CF.
Vázquez scored his first competitive goal on 30 December 2015, replacing Karim Benzema for the final 15 minutes of the league fixture against Real Sociedad and netting in a 3–1 success at the Santiago Bernabéu Stadium. He contributed with seven appearances in the season's UEFA Champions League, as the tournament ended in a win; in the final against Atlético Madrid, he again came on for the Frenchman late into the second half of a 1–1 draw, and converted his attempt in the penalty shootout triumph.